This Nutrients National Synthesis Project site on the U.S. study of nutrients, especially nitrogen and phosphorus, as contaminants in high concentrations links to an overview, study team, featured reports, publications, and national datasets.

Branch of Quality Systems monitors the consistent collection and reporting of water-quality data with documentation of field and laboratory methods and proficiency testing. Links to standard reference samples and quality assurance standards.

Overview of microbiology projects related to water quality investigating bacteria, viral and protozoan pathogens and indicators in the environment with links to publications, analytical and field methods, laboratory, and current projects.